Creating a variable
A variable is a placeholder ( a name, a label, a tag) given to an address ( a memory location) of a value in memory.
You can think of a variable as a box, which has a name. This box will have a value. Whenever we reference ( call) this variable ( name of the address), we then get the value stored at that address.
To create a variable and assign it a value, all we have to think about is an equation.
Eg: x = 2 . x is the variable ( the placeholder) that points to the address of the value, 2. So 2 is the value. A single ( one) equal-to sign, =, is known as the assignment operator. It takes what is on the right ( the value) and assigns ( puts) it into what is on the left ( the variable).
In Python, the data type of a value is controlled dynamically ( meaning as the program runs) so we don't have to worry about it ( memory management).
More examples:
All these are examples of variable assignment ( variable creation) of different data types.
Rules
- variable names can start with a letter or an underscore
- followed by a letter, an underscore or a number
- a variable name can not begin with a number or dot or special symbols (+, -, /, *, and others)
- a variable name can not have white-space characters (space, newline, tab, and others)
Practicals
- Create ten variables and assign them any values suitable ( perhaps, as above).
Summary:
- Variable represents the name given to the memory address.
- Calling the variable returns the value
- The value stored in a variable can change anytime - that's why we call it a variable
- To create a variable, think about an equation, LHS = RHS. LSH is the variable_name, RHS is the value.
Eg: full name = "John Doe"
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